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Abrasive Blasting SafetyControl Measures and Precautions for Sand Blasting

What is Abrasive Blasting?
Abrasive or Sand blasting means propelling a stream of abrasive material at high speed against a surface using compressed air, liquid, steam, centrifugal wheels or paddles to clean, abrade,etch or otherwise change the original appearance or condition of the surface.
It is used in a wide range of industries for many different purposes, including cleaning
surfaces such as steel, bricks, cement and concrete. The most common method uses
compressed air to propel abrasive material from a blast pot, through a blasting hose to
a nozzle that is manually controlled by the operator. Automated abrasive blasting machines
such as centrifugal wheel systems and tumblers are also used. Blasting is generally
performed in enclosed environments like blasting chambers or cabinets, or on open sites,
for example on buildings, bridges, tanks, boats or mobile plant.
Common hazards include dusts, hazardous chemicals and risks associated with the use
of plant and equipment. 


Airborne dust: This is one of the most serious hazards associated with blasting operations. When evaluating this hazard, it's important to consider the concentration of dust and the size of particles. Larger particles, considered "nuisance" dust, are normally filtered out in the nose and throat. Smaller particles (10 microns or smaller) can bypass the lung's filtering system and penetrate deep into the respiratory system, where they may cause serious damage. Safeguards are needed when smaller particles are present in the working environment.

Metal dust : Metal dust, in addition to the abrasive being used, contributes to the generation of airborne dust. Metals such as lead, cadmium, and manganese, can be extremely toxic when inhaled. Many existing paints have a lead base. Regulations require special handling, trained personnel, and medical monitoring when lead is present. If in doubt, check it out. Don't guess.

Silica sand: This product is a potentially serious health hazard and should not be used as an abrasive. If silica containing (quartz) materials are selected for any reason, workers must wear a positive pressure or pressure demand respirator with an assigned protection factor (APF) of either 1000 or 2000. Silica must be contained and disposed of properly. Even if a wet blasting method is selected, silica that is allowed to migrate by either wind or water, will eventually become an airborne contaminant.

Air supply: Air-supplied respirators must be used (1) when working inside of blast cleaning rooms, (2) when using portable units in areas without enclosure, and (3) under any circumstances where the operator is not physically separated from the abrasive material by an exhausted enclosure. If airline respirators and compressors are used, make sure the intake hose is placed in an area that provides clean air. An attendant should be in the area at all times, monitoring breathing air and assuring the blaster's safety.
Additional personal protective equipment: Blasting operations create high noise levels, so hearing protection is a must--for both the operator and nearby workers! Operators should also use heavy canvas or leather gloves, aprons, or leggings when appropriate, as well as safety shoes.

Abrasive blasting hazards include:

  • „ airborne contaminants such as dust
  • „ hazardous chemicals, particulate matter, for example small particles or pieces of the substrate or blasting medium
  • „ noise
  • „ abrasive blasting plant and equipment



 THE RISKS FROM DUST EXPOSURE
There are a number of factors that affect the degree of risk associated with dust produced
in abrasive blasting activities. 
These factors include:
  • „ the concentration of airborne dust in the breathing zone of the worker
  • „ the size of the dust particles generated (whether dust particles are inhalable or respirable)
  • „ the duration of exposure, and
  • „ the type of dust and its biological effect
PERSONAL PROTECTIVE EQUIPMENT
PPE should include:
  • „ an airline respirator of the hood or helmet type, fitted with an inner bib and a high visibility shoulder cape
  • „ protective clothing (a jacket or protective suit)
  • „ protective gloves (canvas or leather)protective footwear
  • „ personal hearing protectors.

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